Background: After one year of the pandemic, Indonesia experienced a crisis where the addition of COVID-19 cases increased significantly in several big cities; it made the healthcare system collapse, including the intensive care unit (ICU) service for COVID-19. ICU nurses, who are at the frontline of fighting against COVID-19 and defusing this crisis, are faced with various challenges in providing care for COVID-19 patients, and exploring such challenges are significant. Purpose: This study aimed to explore the challenges experienced by Indonesian nurses who work in the ICU caring for COVID-19 patients.Methods: A multi-centered-qualitative study with a descriptive phenomenological design was used. Twenty nurses working in the ICU of COVID-19 in eight COVID-19 referral hospitals in seven major cities in Indonesia were recruited using purposive sampling. Semi-structured individual video call interviews were conducted to collect the data from July-September 2021. Data were analyzed using Colaizzi’s (1978) method.Results: The nurses reported the challenges throughout caring for COVID-19 patients in ICU, which are described in four major themes: (a) working under pressure and moral distress, (b) choosing to do the best, (c) adaptation, learning, and research, and (e) survive physically and mentally healthy.Conclusion: This study describes the challenges experienced by nurses working in ICUs during the COVID-19 crisis, such as working under pressure, facing dilemmas caring for patients, and trying to survive working in inadequate professional conditions. An in-depth understanding of these challenges in the current pandemic can help managers in the hospital to provide psychological support, adequate training for ICU nurses, and high-quality protocols for upcoming emergency scenarios, as well as maximizing resource management (human and material).